The technology herein relates to the field of aircraft maintenance, and more particularly to the transmission of data between an aircraft and a ground station in order to facilitate aircraft maintenance operations.
Aircraft, particularly modern transport airplanes, generally comprise a Central Maintenance Computer, generally referred to as a CMC, or a Central Maintenance System (CMS). The central maintenance computer is connected to a set of further computers carried onboard an aircraft and relating to various systems of the aircraft, such as, flight control systems, systems for controlling and monitoring the engines, managing the fuel, etc. The central maintenance computer receives from the other onboard computers data relating to failures of the systems, generally by means of signals of the Built-In-Test-Equipment (BITE) type. The central maintenance computer thus centralizes a set of maintenance data relating to the status of various aircraft systems, particularly relating to potential failures of the systems. The maintenance data centralized by the central maintenance computer thus correspond to maintenance data coming from the various aforementioned systems, without there being any need for the central maintenance computer to interpret this maintenance data in order to discover the status of the systems.
During a flight of the aircraft, the central maintenance computer records the maintenance data relating to the aircraft systems and produces a maintenance report. The maintenance report comprises at least a significant proportion of the data relating to the status of the aircraft systems. The central maintenance computer records the maintenance report at the end of the flight (generally referred to as a post flight report). The post flight maintenance report is generally used by a maintenance operator to determine what maintenance operations to carry out on the aircraft. During the maintenance operations, the maintenance operator can also consult the current status of the aircraft systems, particularly potential failures thereof, via a screen interfaced with the central maintenance computer. During the flight of the aircraft, a subset of the maintenance report in the process of being recorded may also be sent to a ground station, for example a maintenance center of the airline operating the aircraft. The subset is generally sent by means of a communication of the ACARS (Aircraft Communications Addressing and Reporting System) type. The sending of the subset is performed cyclically, at a predetermined time interval that may be dependent on the model of aircraft, usually every 15 minutes. The data to be sent is limited to the subset of the maintenance report so as to limit the volume of data that has to be transmitted from the aircraft to the ground station, given the high cost of communications of the ACARS type. The subset corresponds to a predetermined selection of data from among the data recorded in the maintenance report. The subset will be referred to as a current maintenance report in the remainder of this description.
An aircraft also generally comprises an Aircraft Condition Monitoring System (ACMS). The ACMS system monitors the flight data of the aircraft. The aircraft flight data may correspond to data from sensors or other equipment of the aircraft, for example the current performance of the aircraft, aircraft speed data, data relating to the operation of the aircraft engines (temperature, etc.), etc. An ACMS system is configured to produce reports corresponding to a predetermined set of aircraft data. These reports are generally referred to as ACMS reports or Aircraft Integrated Data System (AIDS) reports. These reports may be defined by the constructor of the aircraft or by the airline operating the aircraft, by means of dedicated programming installed by an operator operating onboard the aircraft. The ACMS system may also be configured to send these reports to a ground station, generally by means of a communication of the ACARS type. In particular, these reports may be produced by the ACMS system and sent to the ground station when a condition regarding the predetermined set of aircraft data is satisfied, for example in the event of an anomaly with values of some of the data.
However, in the event of an aircraft system has a fault, such reports reveal only the consequences that the aircraft flight data has a fault, but do not always contain data that allows directly identifying the origin of the fault. On the basis of an ACMS report, a ground station operator may generally at most suspect a certain number of aircraft systems, but may not have any certainty as to which of these systems is actually faulty. In order to identify a faulty system, the operator generally consults the last current maintenance report(s) sent by the Central Maintenance Computer (CMC) to the ground station. However, as discussed previously, the current maintenance reports sent by the central maintenance computer contain only a subset of the data from the maintenance report. As a result, they may fail to contain the information that would have been useful for the operator in understanding the origin of a fault. In addition, given that the current maintenance reports sent by the central maintenance computer are sent cyclically, in particular every 15 minutes, the data contained in a current maintenance report sent by the central maintenance computer are not synchronized with the data contained in the report sent by the ACMS system. Because these various data correspond to different moments in time, it may be difficult for the operator to correlate them in order to identify the origin of a fault. In addition, as already discussed, the usual interval between two successive transmissions of current maintenance reports by the central maintenance computer to the ground station is relatively long, such as 15 minutes. As a result, the data contained in such a report may be obsolete by the time a report from the ACMS system is received by the ground station. In addition, even if the data contained in the next report allow identifying the origin of the fault, the fact that the maintenance operator has to wait for the next report may induce a significant delay into the analysis of the data by this maintenance operator.